Figure 5. Effect of parasite stimulation on percentage of SITR-positive cells.

A. Density plots of intracellular SITR protein expression analysed by flow cytometry using anti-SITR antibody. Macrophages were stimulated with live T. borreli parasites (0.5×10⁶ per well) for different time periods or left untreated as negative control. Two populations of cells could be defined on the basis of SITR protein expression: SITR^dull and SITR^high for the density plot representing negative control cells at 0.25 h. The separation (grey dashed line) between SITR^dull and SITR^high gates was defined based on each negative control (at 0.25, 0.5, 1, 2 and 3 hours) and set as the line separating the two populations. The same SITR^dull and SITR^high gate settings were used to analyse the parasite-stimulated samples at the respective time points. Density plots shown are representative of one out of three experiments. Mean fluorescent intensity (MFI) of FITC and PE are represented in X and Y axes, respectively. B. Percentage SITR^high cell populations (averages ± SD of n = 3 fish) after stimulation of macrophages with live T. borreli parasites for different time periods, or left untreated as negative control. Symbol (*) indicates a significant (P≤0.05) difference in parasite-stimulated cells compared with unstimulated cells at the same time point.